I apologize for not closing out this topic.
I found the slotted nut was tight, but removed it anyway. Lacking the proper tool, I simply tapped it out with a hammer and punch. A pawn shop sold me a long 1-1/8" 6-sided impact socket whose O.D. was just slightly bigger than the O.D. of the slotted nut. This cost me about six bucks. Using a bench grinder, I ground down the working end of the socket, leaving two opposing nubs about 1/8" long and slightly narrower than the slots in the nut. Having the nut in hand allowed me to fashion the tool to pretty much exactly fit two of the four slots in the nut. I had to do some hand work with a metal file to remove the rounded areas on the side of the nubs (left by the rounded corners of my grinding wheel) so they would fit deep enough into the slots on the nut. I also had to file some of the inside of the socket nubs so they fit. Lastly, I ground down the outside of the socket so the O.D. was slightly less than that of the slotted nut, which is recessed when fitted. I probably had to remove less than ten mils.
The total time to make this tool was about a half hour.
The socket worked just fine. Oddly enough, this solved the speedometer problem. I figured it wouldn't, since the nut was already "tight". Just a bit more torque, using my makeshift tool, worked a treat.
Note 1: The socket I bought was an impact socket. They are possibly made of stronger steel. I was concerned that, gripping the nut in only two slots, one of the nubs might break off. Not to be.
Note 2: A deep socket is necessary so as to clear the transmission shaft.
Note 3: Making a tool with four nubs would be more difficult, using a regular bench grinder. And, while all four nubs might fit into the slots, it is almost a certainty that only two of them will actually contact the slots' surfaces. Since these two could be next to each other, rather than opposing, I preferred to cut only two nubs.
Note 4: Making this tool without first removing the nut would be a pain in the patooty. The nut is hardened, so tapping on it with the punch doesn't mar it.
Note 5: Upon getting to the flex disc, I found that it had not been put on correctly. There are six bolts and nuts, with washers, and they have to be put on a certain way. The man from whom I bought the car is an accomplished mechanic, but he had no idea that his method of attachment could eventually result in disc failure. I suggest that everyone who has never looked at their flex disc do so to ascertain the bolts are fitted correctly.
It is nice to have a working speedometer!
Joe
